1. Technical Field
The present invention relates to assembly machines, more specifically assembly machines for assembling electronic components on to printed circuit boards (PCBs).
2. Related Art
The assembly of electronic components on to printed circuit boards (PCBs) using a PCB assembly machine (hereinafter “machine”) is well known in the art. However, as more and more requests are made for machines that are easily moveable and quickly reconfigurable between lines of machines, the ease of reliably transferring the PCB through the machine becomes problematic. Another area of constant desired improvement is to increase the throughput of the machine while at the same time maintaining, if not reducing, the cost of the machine regardless of the size of the PCB.
Common PCB assembly machines typically comprise a variety of subsystems to facilitate the assembly process. These may include, but are not limited to: a PCB handling system—for transferring at least one PCB into, through, and out of the machine; a feeder system—for supplying electronic components to the machine; a pick and place system—for transferring components from the feeder system to the PCB(s); a vision system—for inspecting, inter alia, the PCB(s) and the components; and a nozzle changer system—for supplying one or more nozzles to the pick and place system.
A typical PCB handling system may comprise separate mechanisms, including, inter alia, multiple rails that carry transport belts to transfer a PCB in and out of the machine. In general, these rails may also include a clamping mechanism to hold the PCB in position while a pick and place system places components on the PCB. Moreover, a typical PCB handling system may include, a first rail located in a fixed position when the PCB handling system is operably connected with a PCB assembly machine. In addition, a second rail of a typical PCB handling system may be movable/adjustable, with respect to the PCB assembly machine, to adapt the handling system to the width of a PCB. The adjust mechanism may be motorized or manual, such as a hand wheel. The rails may be mounted on the machine frame. Alternatively, the rails may be mounted on a separate PCB handling structure assembled outside the machine, which structure may then be operably connected to the PCB assembly machine.
A common feeder system often comprises feeder banks upon which one or more feeders may be mounted in order to supply the electronic components. Additionally, the feeder banks may be located in a fixed position within the PCB assembly machine and may provide support for other subsystems that may be necessary for the assembly of PCBs. Such subsystems may comprise one or more vision systems, and/or one or more nozzle changer systems. Vision systems may be used to acquire images of the components prior to their placement onto a PCB. Nozzle changer systems typically manage additional nozzles either for the replacement of a damaged or contaminated nozzle or for the exchange of one nozzle for another nozzle to accommodate various component holding needs.
In ordinary PCB assembly machines, the distance between the PCB and the component feeder banks is often bigger when the PCB is narrow in width (as shown in FIG. 5A). Moreover, most PCBs are narrow compared to the machines maximum PCB width capability. Accordingly, a typical pick and place system must travel extra distance to pick and place components, which takes extra time; thus, the extra travel distance creates inefficiencies that contribute to lower throughput. Similar inefficiencies hold true for any extra distance various systems of the machine may have to travel in order to obtain images of the components or to exchange nozzles.
Another significant disadvantage of common PCB assembly machines is that it is hard to set the machine up in such a way that the board handlings systems are properly oriented to facilitate transfer of PCBs from one assembly machine to another. For example, fixed rails must be aligned to preceding and/or following machines or conveyors accurately enough to transfer the PCB reliably in and out. To accomplish this, a machine operator typically moves each heavy machine into alignment with the machine or conveyor adjacent to it. This aligning of the entire machine is tedious and cumbersome amounting to extra time and expense.
Accordingly, there exists a need for an improved printed circuit board assembly machine.